ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 4G5 



The part of the rod within the cork was enclosed in a small brass tube, 

 soldered above and below the cork to the body of the Microscope tube. 

 The lowest part of the small brass tube was arranged as a stuffing-box, 

 so that no ingress of external air could take place, but the whole 

 arrangement formed an eccentric focussing device whereby the oiled 

 plate could be made to explore the atmosphere of the condensation 

 chamber, and then rotated for examination into the proper position. 

 The particles observed seem to have varied in diameter between 

 •0003 and '0008 cm. 



Haktmasn, J. — Objectivuntersuchungen. 



[An article full of practical details regarding all varieties of optical errors.] 



Zeitschr. Imtrumentenk., xxiv. (Jan. 1904) pp. 1-12 

 (9 figs., 7 numerical tables). 



Plank, M. — Tiber die Extinction des Licbtes in einen optischhomogenen Medium 

 von normaler Dispersion. 



[The author compares his results with those of Lord Rayleigh's paper, and 

 finds that they agree.] S.B. K6nig.preuasich.en Akad.der Wis*. 



xxii. (April 1904) pp. 740-50. 



Sato Tscneji — Zur Mikroskopiscben Technik. 



[Recommendation to insert coloured glass or gelatin-paper between the mirror 

 and condenser when examining by artificial light. Complementary colours 

 should be employed, e.g. for saffranin, green ; for methylen-blue, orange ] 



Munchener Med. Wochenschr., 1. (1903) p. 327. 



(6) Miscellaneous. 



Electro- thermic Regulator and Electric Incubators.* — CI. Regaud 

 and R. Fouilliand have applied the principles, considered by them in 

 an earlier memoir, f to the construction of thermostats for biological 

 laboratories. The subject is considered under five heads : (1) Mode of 

 heating ; (2) mode of regulation ; (3) various details of construction ; 

 (4) practical results ; (5) review of previous works upon electric 

 heating and regulation of stoves. 



Mode of Heating. The heat is entirely furnished from within, and 

 is radiated from a series of bare wires coiled along the walls and floor 

 of the cupboard. This method is considered much superior to one of 

 radiation from a focus, such as an electric incandescent lamp. To 

 produce uniformity of temperature the number of coils is diminished 

 in the upper tiers and no coils are placed in the ceiling (fig. 71). 



Mode of Regulation. The regulation, which is obviously of capital 

 importance, is shown in fig. 72. It consists of a tube ABCD bent 

 into a U. The part A B, or ampulla, is relatively wide and thin- 

 walled ; B C D is narrow and thick- walled. To the lower part of the 

 ampulla a pouch Gr is soldered on. The wall of the thick tube is 

 pierced by two platinum threads placed opposite one another. One of 

 these tubes, E, is bent in the axis of the tube, and its pointed interior 

 extremity is directed towards the elbow C ; the other, F, is straight. 

 The regulator is completely closed, and the extremities of the pouch G- 



* Zeitschr. wiss. Mikr., xx. (1903) pp. 138-68 (S figs.). 



t Chauffage et re'gulation des e'tuves par l'e'lectricite'. Jouni. do Physiol, et do 

 Pathol. Ge'ne'voise, 1900, p. 457. 



Aug. 17th, 1904 2 k 



